[ToddA1]

... if your running LED bulbs.

Hella H4 housings (DOT approved) with Standard Hella 55/60W bulb. LED is rated at 26W and 6000K.

Nothing is adjusted. This was a quick curiosity thing, prior to road testing the GTI. It’s been over a year, since it saw the road... iPhone 11 was clamped in place and all pics taken within a few minutes of each other.

Relayed LED bulb on the right and relayed halogen, on the left.

Relayed LED on the left, with non relayed LED on the right.

High beams on relayed and non-relayed LEDs

Low beams on both relayed LEDs.

I was originally going to install the used stuff, then thought about LED. I was thinking about LED bulbs not being too voltage sensitive, when I was halfway done building the harness, so I keep going.

I see no difference... I could have saved myself a few hours and a few bucks in Hella and Metripack connectors....

-Todd

 

[Butcher]

I believe LED's use much less current than standard bulbs so a relay may not be worth the additional hassles.

 

[briano1234]

Relaying your headlights is a good thing. It is the Voltage and the Current that you are increasing at the lamp via the relay, it is the Higher Current off load from the switch that will save you in the long run using stock lamps.

On my Cabbies I noticed the Voltage difference at the lamps of the left was 1/2 a volt different than my right, that is I had 11V on the Right and 11.6 on the left. With the Relays I went to 13.5 on both. Now if you do the 3 relay conversion then you get all the highs and low filaments firing at the same time...

Granted LEDs use way less current than stock. But you are still off loading your supply current off the switch which is a good thing.

Your photos remind me of the old days in the mid 70's when I went from incandescent bulbs to Cibie Quartz... old yellow vs white, once I added relays even back then they got brighter.... Don't know how many folks flashed their lights at me because they thought that I had my brights on..... I can't imagine their face on the interstate when I flashed my brights on.

 

[ToddA1]

As mentioned LEDs have a very wide voltage range, as opposed to incandescents, which is why I wasn’t expecting much.

The current draw is minimal, on these LEDs... less than 4A, if factoring 13.8V. I’d think any headlight switch would be able to handle that.

I remember running 90/130W bulbs and continually burning out switches, in the early 90s. Parts were plentiful and it was easier to just replace the switch, lol.

Maybe I’ll add a jumper and diode to the relays to allow both high and low to run simultaneously. No additional relay would be needed. I’d still be under 8A, total.

-Todd

 

[fatmobile]

Right, the light switch is also something to concider.
As the contacts get old they build up resistance.
Which causes heat and melts the switch and plug.

8amps,..
what do stock headlights draw?

 

[briano1234]

Well the lows on my cabby are using 10A fuses and there are 2 of those for lows and 2 of them for highs. then you would have to add the parking lights, tail lights as going through that switch as well.

 

[Aug]

Relays also take the load off the headlight switch..... runs cooler and won’t burn out as much.....

 

[BMAN]

I added these LED lights with relay harness to my GTI just before putting it away for winter. Didn't get a chance to try them out at night, but I can see a big difference in the brightness.

 

[Butcher]

Everyone talks about how great relays are and someone brings up the thought that it may be unnecessary and they get beat up.

Relays have their purpose. They take the load away from a switch that was designed to handle a certain load and transfer that load to another component that is designed to carry that same load. More components and wiring may not be that beneficial.

The guy is using LED's. I have no idea how much load they are consuming, but if someone told me it was half the amount, I would not disagree. To add relays to a circuit that was designed to carry 10 amp and is know carrying 5A seems to be a waste of time. It just adds complexity and more things to go wrong in the future.

The OP is saying that adding relays on a reduced load circuit may be a waste of time. He is 100% right.

 

[ToddA1]

Well the lows on my cabby are using 10A fuses and there are 2 of those for lows and 2 of them for highs.

You have a 10A fuse for each of your low beams and a 10A fuse for each of your high beams... a total of 4 fuses? That seems ridiculous.... if your running 55w lows, , that’s a 8A draw for both lows @ 13.8v.

The OP is saying that adding relays on a reduced load circuit may be a waste of time. He is 100% right.

Exactly. I spent hours on this harness, and it’s a waste of time and money. The switch should have no issues with 4A or 8A, if I decide to run the highs and lows simultaneously. The only time I’ve ever had switches go bad, was when I was runny crazy wattage bulbs.

I am running LED bulbs in the tails and turns, but it has nothing to do with the switch. US tail lights are getting increasingly hard to find and the prices are skyrocketing. These tails like to warp and crack and my set were NOS Hellas, from years ago.... I’m not knowing going to ruin them.

Anyhow, since I’m in the process of making the car purity, I needed to address the rusting headlights; the buckets were already powder coated.

The color is called ”aged rust”... so fitting.

That’s a new Hella e-code, to the right. The slivering was beat, so just sprayed the entire rear. Easier than trying to replicate that brown/silver fade.

I’m happy with how they came out. Just need to adjust everything, and this part is complete.

-Todd

 

[ToddA1]

8amps,..
what do stock headlights draw?

I think low beams in sealed halogens are 35W? If so, a pair would draw 5A @ 13.8v. I’m not sure what the high beam wattage is, but I doubt it’s more than 55W.

-Todd

 

[rabbitnothopper]

measure the voltage at the headlight plug.
without relays you will have ~10-10.5 volts DC
with relay you will have ~12-13VDC

if you have less volts then you will use more amps
on the old wiring more amps = more heat. thats the problem
thats why you relay
new wires + relays takes the load off the headlight switch & highbeam switch.

even if you use LED there is no argument about it.

 

[ToddA1]

Amperage does not increase with voltage, on a resistive load circuit. Incandescent bulbs are a resistive load. The heat increase is due to resistance In the old wire and contacts.

Yes, it’s reducing load at the switch, but the lighting output is the same, with LED, whether relayed or not. When most people run relays on incandescent bulbs, it’s usually for higher lighting output.... less load at the switch is a bonus.

These LEDs have an input range of 9-32V, meaning they’ll perform the same, between that range. If your voltage is less than 9V, you have a bigger issue, which needs to be addressed. Again, I don’t think relaying these are worth it, because of the lower voltage requirements and lower amperage draw. This is my opinion, but feel free to run relays on what you like.

-Todd

 

[sgnimj96]

gotta have LED housings for led bulbs , the advertising that says different is BS

 

[ToddA1]

I did some quick voltage tests while I was playing with fuel pressures.

Voltage, taken from the battery terminals- 12.48
Voltage taken from the relayed ow beam plug (long lead) - 12.42
Voltage taken from the non relayed low beam plug (long lead)- 12.36

Not too much of a voltage drop.

My readings may be a bit higher than normal, since my fuse/relay panel was replaced... it was in pretty bad shape.

During this replacement, every plug In every harness, I could depin was taken apart, cleaned and reassembled. 10 gauge feeders were run from the battery to the fuse/relay panel.

-Todd

 

[Butcher]

If you keep throwing facts out there, you are just going to make relay lovers upset.

God bless simplicity.

 

[fatmobile]

LEDs don't usually run straight from a battery.
They normally have some type of current or voltage regulator powering them.
Since 9 volts is the lowest supply voltage allowed,
they probably run on 9 volts and anything above that for input is regulated down to 9 volts.
They won't dim as the battery goes down.

Hard to imagine the supply voltage dropping below 9 volts.
Relays or not.
If that happens you have bigger problems, ha.